The provider heading's status slot now shows a fuel gauge for the
tightest usage window: hidden while there's room, "17% left · resets
3:00 PM" at 20% or less (amber from 10%), with a bar along its bottom
edge for what's left, then the existing "Limited until" once the login
is out. Hovering lists every window (5-hour, weekly, per-family).
model.options attaches `usage: { windows }` from a per-profile cache in
agent/account_usage_cache.py and refreshes it in the background, so the
picker never waits on a usage API. Every fetch_account_usage call lands
in that cache, including the one session.usage runs after each turn, so
the chip is at most a turn or two minutes behind. Covers the built-in
fetchers (Anthropic, Codex, OpenRouter) and any provider plugin's usage
hook.
Both pickers now render one ProviderStatusChip instead of separate
limit badges.
